Rotary machines typically utilize vane motors that are pneumatically powered to cause rotation of the output shaft. As is well known these machines comprise a cylinder, sometimes referred to as a casing and an eccentrically mounted spindle in the cylinder, sometimes referred to as a rotor. The cylinder is stationary and through apertures in the cylinder lead pressurized air to impinge on the working face of the reciprocating vanes mounted in slots formed in the spindle to cause the spindle to rotate and then exhaust the spent air through additional holes formed in the cylinder. The outer edge of the vanes is in contact with the inner surface of the cylinder and the vanes extend in their respective slots during the power stroke of the vane motor and during the exhaust portion of the stroke the vanes retract back into their respective slots. Heretofore, the cylinder had apertures formed therein that were configured in the shape of slots. The pressurized air that is admitted to the spindle and impinges on the working face of the vanes to cause them to rotate the spindle.
This invention is directed toward the interface between the spindle and cylinder so as to enhance the sealing of the gap between the two components resulting in an improvement in the requirements to lubricate the vane motor and rotating machine. The terms “seal” and “sealing” in the context of this application does not refer to independent hardware that typically is inserted at strategic areas in the rotating machine to prevent or reduce leakage, but rather to the configuration of the complementary components that are contoured to reduce the gap between the interfacing parts and therefore eliminate or reduce leakage of fluid from upstream of the configuration to downstream thereof. When this inventive feature is employed in a cylinder at the interface of the cylinder and spindle of a vane motor so as to configure the surface of the inner diameter of the cylinder shape of this surface this change contours this surface from a circular shape to a crescent shape. Accordingly, for use in this description this portion of the interface os referenced as a crescent seal.